Lord Myners - plain Paul until three days ago - knows about being thrown in at the deep end. Barely 20 days into his new role as City minister, Myners has already helped orchestrate a historic bail-out of the British banking system and told the bosses of three of our biggest banks that the taxpayer is taking up to £37bn-worth of stakes in their business so they might survive the economic turmoil.

The intensity of the workload has been extraordinary but there is little time to rest. Insurance companies and hedge funds are now being scrutinised. A crucial bill to update a bank regulatory system exposed by Northern Rock's collapse last year must be raced through parliament as the government tries to marshal an international response to the crisis.

Myners, who until he took ministerial office was chairman of Guardian Media Group, which publishes the Guardian, will be in the thick of it as Alistair Darling's point man with the City. The Bank of England governor, Mervyn King, admitted this week that the banking system had been the closest to collapse since the first world war, but Myners insists: "We are now in a much better place. That's not to say everything has been addressed. We remain alert to shocks [but] I feel we are on top of the situation in terms of anticipating where challenges could arise."

His appointment on October 3 came as part of Gordon Brown's ministerial reshuffle, which also heralded Peter Mandelson's surprise return to the cabinet. Myners' involvement in Brown's emergency changes also raised eyebrows. The 60-year-old businessman, who favours open-neck shirts rather than ties, held a string of top jobs and forfeited £1m of income to take on the role. As well as chairman's roles at GMG, the FTSE-100 property company Land Securities and the Tate Gallery trustees, he resigned as a director from GLG, a hedge fund that profited from placing bets that bank stocks would fall. Such short-selling is now temporarily banned by the City regulator, allowing the Conservatives to accuse Brown of hypocrisy.

When Myners joined the government he knew he would be thrown headlong into the crisis - which had yet to reach its climax - at Britain's banks. "I'm a minor support act for the chancellor but I knew I was coming into his team with a specific responsibility in this area." His immediate brief was to work with Darling to re-establish confidence in the British banking system.

Orphanage

Described as having a ferocious temper and a considerable ego, Myners has had some experience of a banking crisis before. He was a reporter at the Daily Telegraph during the banks' last big wobble in 1973. His view is that the secondary banking crisis - which affected dozens of smaller banks - "was infinitely simpler" than the current one. Did he get scoops? "Yeah," he says. Was he a good reporter? "I made up for lack of flair and skill with energy and hard work, and I think that's often been a feature of my life."

Adopted from a Bath orphanage by a Cornish couple - he told the Guardian in the past that "I know nothing about my natural parents; I don't wish to" - he went to school in Truro and did a degree in education. He taught for a while, did a stint in the City and after the Telegraph, joined NM Rothschild where he spent 10 years before joining fund manager Gartmore. It was here he made his name in the City and an estimated £30m fortune. In 2000 he went plural, taking several boardroom seats including the chairmanship of Marks & Spencer as it faced down a potential bid from the retailer Sir Philip Green.

The experience with Green - who said he wanted to give Myners "a proper fucking kick in the head" the night he dropped his bid - has left its mark on the new City minister in his frantic efforts to prop up the ailing banks.

"In my working life I've been through many critical days. The one that springs to mind is around the Philip Green bid for M&S. This [bank rescue] is no different in that there are days of great intensity when you know that there are crucial moments," says Myners, who reluctantly resigned from M&S after another director queried his friendship with the chief executive, Sir Stuart Rose

At ease with the media, his answers are fluid and well rehearsed. He is quick to express an opinion. Before taking this role, he laid into the boards of British banks and criticised private equity firms. Uncharacteristically, he stumbles when asked who can be blamed for the current crisis. He starts well: "It's a global phenomenon ... It's a situation where everybody has lessons to learn." On the Financial Services Authority, which admitted its poor handling of the Northern Rock affair, he says: "Adair [Turner, FSA chairman] is talking about the need to change the way the FSA defines its role and the Treasury is working with him on that."

When he gets to the Bank of England, he "struggles". Until three weeks ago he was a member of its Court - equivalent to a company's board. The silences speak volumes. It takes 15 seconds before he says: "I think"; five more to begin: "The Bank of England has some lessons to learn ..." before trailing off again. A minute later, he has his lines: "The Bank of England has two core responsibilities: monetary policy and financial stability. [With] monetary policy, it has clearly performed its role to extraordinarily high standards. On financial stability, it has been hampered by the limited instruments available to it, which is one of the reasons we're proposing new legislation to give the bank more power to perform its statutory obligations," he says, relieved at finding the politician's answer.

Social justice

Although he says he never aspired to a political life and only joined the Labour party to take on the City minister role, he has led several government reviews. "I've always been deeply concerned about equity and social justice," he says - liberal with a small l.

He cites his role as chairman of the Low Pay Commission as evidence of his concern about pay inequality. But he rejects the idea that taxpayers' stakes in banks could be used to re-engineer the social order. "The government doesn't have a policy objective to own banks ... they are not agencies of social change. The government has other instruments to achieve those goals."

The government is forcing the bail-out banks - Royal Bank of Scotland and the combined Lloyds TSB and HBOS - to put lending back on a 2007 footing to keep the financing tap on for small business and would-be home-owners during the oncoming recession. The government will also get some say over appointments to boards and secured pledges that bosses will not get bonuses.

The exact way the government will oversee the £37bn at risk is still being ironed out, but Myners reveals a new agency is likely to be created similar to the Shareholder Executive set up in 2003 to oversee government stakes in businesses such as the Tote, Channel Four and the Met Office. It has since nationalised Northern Rock and it is not clear whether this stake will be under the new agency.

Myners reckons the insurers and the hedge fund industry are not in the state in which the banks ended up a fortnight ago. "We are watching those situations carefully," he admits, but insists the taxpayer will not have to prop them up. He puts the onus on the FSA, which he says has "taken some major steps across all its areas of responsibility to revisit areas of capitalisation".

He does not take issue with the idea he has a bad temper but prefers to call himself passionate. But he is affronted by the idea that he has a big ego or is a major networker, insisting he is not a fan of cocktail parties - not least because he is being fitted with a hearing aid.

It is not clear how long Myners, who is not taking a ministerial salary, hopes to be City minister, a role that until a year ago would have been more about defending taxing non-doms or big firms threatening to leave the UK for more relaxed tax regimes than fighting for the City's survival. He is doing it out of a sense of public duty as his wealth means he does not need to work. "I just like to be involved. I love challenges and can't contemplate how one could be satisfied sitting on the beach," he says.